A respiratory assistance system including a humidification apparatus may be used to deliver heated and humidified respiratory gases to a patient through a conduit and a patient interface. The respiratory assistance system can provide a number of therapies for patients requiring respiratory support. One of the therapies includes providing a high flow therapy. In high flow therapy, the respiratory support system delivers relatively high flows of gases through an interface, such as an unsealed nasal cannula. The flow rate of gases can be in the range of 5 L/min to 120 L/min for patients.